Telephone.



No. 732,443. PATENTED JUNE 30, 1 903.

F. c. REDFIELD.

TELEPHONE.

APPLICATION FILED APE. 3.1902.

NO MODEL.

m: NORRIS runs 00. vac-rammed WASHINGTON. u u.

UNITED STATES Patented June 30, 1903.

PATENT OFFICE.

FRED C. REDFIELD, OF NASHUA, NEW HAMPSHIRE, ASSIGNOR TO THE AMERICAN OTOPHONE COMPANY,

CORPORATION OF MAINE.

OF NASHUA, NEW HAMPSHIRE, A

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 732,443, dated June 30, 1903. Application filed April 3, 1902. Serial No. 101 ,258. (No model.)

To all whom it may concern.-

. Be it known that I, FRED O. REDFIELD, of Nashua, in the county of Hillsboro and State of New Hampshire,have invented certain new and useful Improvements in Telephones, of which the following is a specification.

This invention relates to telephones in which'a series of harmonic vibrators are employed vibrating harmonically or consonantly with the vibrations of the diaphragm of the telephone instrument and responsive to diiferent tones of the human voice or other sounds impressed upon the telephone.

The object of the invention is to obtain greater delicacy and distinctness of tone in instruments of this character without the necessity for increasing the battery-current.

In some respects the present invention is an improvement on the telephonic transmitter patented by Lemuel Mellett, dated Feb-' ruary 5, 1901, No. 667,546, in which are employed a series of harmonic vibrators located behind a diaphragm and vibrated thereby and reacting upon the resistance-varying element, which consists of a body of loose granular material held between electrodes, the distance between-Which is varied by the vibration of the diaphragm. The theory advanced in this patent as to the effect of the vibrators, and which I believe to be the correct theory governing the operation of the transmitter hereinafter disclosed, is that the vibrators becoming consonantly or harmonically vibrated by the diaphragm impart a minute agitation to the whole body of granular resistance-varying material, which increases the looseness of the body and gives it greater responsiveness to the immediately-succeedin g tone or tones impressed upon the diaphragm.

One object of my present invention is to enhance this efiect of the vibrators upon the resistance varying element by applying a resonator to the instrument;

It is also the object of the invention broadly to increase the effect of harmonic vibrators in a telephone by the use of a resonator.

A further object is to provide an improved manner'of mounting the vibrators in a telephone of this character.

Of the accompanying drawings, Figurel represents an axial section of a transmitter constructed in accordance with my invention. Fig. Q'represents a section on line 2 2 of Fig. 1.

The same reference characters indicate the same parts in both figures.

In the drawings, 10 represents a casing having a mouthpiece 11 and a diaphragm 12 mounted behind said mouthpiece" in the ordinary manner.

13 represents the resistance-varying element connected with the diaphragm bya stem 14 and comprising, as here shown, an electrode 15, vibrated by the stem, a fixed electrode 16, attached to a bridge or bracket 17, spanning the casing, and an interposed body of loose granular resistance-varying material 18, such as carbon. The circuit is made through a wire 19, the casing 10, the bridge 17, the electrode 16, the granular carbon18, the electrode 15, the stem 14, the diaphragm 12, and a wire 20. p

Immediately behind the diaphragm 12 is a hub 21, attached to the stem 14, and in the flange of which are secured the inner ends of a series of outwardly-radiating vibrators 22 22, shown in the form of coils of wire which are made of different lengths and responsive to different tones 'or sounds. Preferably a whole gamut of eight tones should be provided for, and I have here shown a double gamut of sixteen vibrators. The different tones of the voice or other sounds received upon the diaphragm 12 have the eifect of setting dilferent ones of the vibrators 22 in a state of vibration which continues after the tone itself has ceased. Thus the carbon-cell is continued in a state of minute agitation for a short time after a tone has passed,

1 whereby the adhesion or static friction of the loose grains of the cell is overcome and the quickness with which they will slide upon each other in response to the immediately succeeding tone or tones is greatly increased.

This increases the sensitiveness of the instrument, and the harmonic vibrators on the principle of consonent or harmonic vibration give a greater loudness and full quality to the tones passing through the instrument.

On the stem 14 between the vibrators 12 and the carbon-cell 13 I mount a resonant disk or resonator 23, preferably made of a material such as well-seasoned wood of a 13 quality which would be considered suitable for the bodies of violins or other stringed musical instruments. This disk 23 acts as a resonator upon the same principle as the body of a violin or other stringed musical inr strument or a wooden box placed against the stem of a vibrating tuning fork. It enhances the effect of the vibrators and diaphragm upon the resistance-varying element partly by transmitting the'vibrations of the vibrators 22 to the whole body of air within the chamber back of the diaphragm and also establishes a greater harmonic reaction between the diaphragm and vibrators, with the effect of increasing the loudness of tone trans- 25 mitted by the instrument without necessitating an increase in battery-current and without any of the evil eifects of such an increase in current. I do not wholly restrict myself to the exact position or construction of the 0 resonator.

By mounting the vibrators in outwardlyradiating arrangement upon a central hub I provide a compact structure and one in which the vibrators may be easily applied to their support in the course of manufacture. It will, furthermore, be noted that the vibrators and resonator are connected with each other and with the vibrating part of the diaphragm in the sense of being attached directly thereto and not indirectly through the edges of the diaphragm and the walls of the casing.

The vibrations of the diaphragm are thus transmitted directly and without loss of force to the vibrators and resonator.

I claim 1. In a telephone, the combination of a diaphragm, and means located behind said diaphragm and including a series of harmonic vibrators, and a resonator.

2. In a telephone, the combination of a diaphragm, and means located behind said diaphragm and including a series of harmonic vibrators connected therewith, and a resonator.

3. In a telephone, the combination of a diaphragm, and means located behind said (liaphragm and including a series of harmonic vibrators, and a resonator connected with said vibrators.

4. In a telephone, the combination of a diaphragm, and means located behind said diaphragm and including a series of harmonic vibrators, and aresonator connected with said diaphragm.

5. In a telephone, the combination of a diaphragm, and means located behind said diaphragm and including a series of harmonic vibrators and a resonator connected to each other and to the diaphragm.

6. In a telephone-transmitter, the combination of a diaphragm, and means located behind said diaphragm and including a resistance-varying element affected thereby, a series of harmonic vibrators, and a resonator.

7. In a telephone-transmitter, the combination of a diaphragm, and means located behind said diaphragm and including a resistance-varying element alfected thereby, a series of harmonic vibrators connected with said diaphragm, and a resonator.

S. In atelephone-transmitter, the combination of a diaphragm, and means located behind said diaphragm and including a resistance-varying element atfected thereby, a series of harmonic vibrators, and a resonator connected with said vibrators.

9. In a telephone-transmitter, the combination of a diaphragm, and means located behind said diaphragm and including a resistance-varying element atfected thereby, a series of harmonic vibrators, and a resonator connected with said diaphragm.

10. In a telephone-transmitter, the combination of a diaphragm, and means located behind said diaphragm and including a resistance-varying element affected thereby, a series of harmonic vibrators, and a resonator all connected together and to the diaphragm.

11. In a telephone-transmitter, the combination of a diaphragm, a resistance-varying element affected thereby, a series of harmonic vibrators between said diaphragm and resistance-varying element, and a resonator between said vibrators and element.

12. In a telephone-transmitter, the combination of a diaphragm, a resistance-varying element, a stem connective of said diaphragm and element, a. series of harmonic vibrators attached to said stem, and a resonator attached to said stem.

13. In a telephone-transmitter, the combination of a diaphragm, a resistance-varying element, a stem connective of said diaphragm and element, a series of harmonic vibrators attached to said stem behind the diaphragm, and a resonator attached to said stem between the vibrators and the resistance-varying element.

14. In a telephone-transmitter, the combination ofa diaphragm, aseries of harmonic vibrators located behind and connected with said diaphragm, and a body of granular resistance-varying material affected by said diaphragm and vibrators.

15. In a telephone-transmitter, the combination of a diaphragm, a series of harmonic vibrators located behind and connected with said diaphragm, and a body of granular resistance-varying material connected with said diaphragm and vibrators.

16. In a telephone-transmitter, the combination of a diaphragm, and means located be- ICC hind said diaphragmand including a resist- I stem, and aseries of outwardly-radiating har- IO ance-varyingelementaffected thereby, a hub, monic Vibrators attached to said hub.

and a series of outwardly-radiating vibrators In testimony whereof I have affixed my sigattached to said hub. nature in presence of two witnesses.

17. In a telephone-transmitter, the combination'of a diaphragm, and means located be- FRED REDFIELD' hind said diaphragm and including a resistfitnesses: ance-varying element, a stern conneqtive of WM. E. SPAULDING, said diaphragm and element, a hub on said GEO. W. CAMPBELL. 

